The 71-year-old recently called time on 26-and-a-half years managing in the country, and feels the game is in far greater shape now then when he joined Manchester United
The Scot stepped down from the Old Trafford hotseat after more than 26 years at the helm, bringing an end to a trophy-laden era for the club.
And Sir Alex believes United "symbolised the transformation of the English game during the Premier League years", with the fan experience particularly benefitting following the dark days of Heysel and Hillsborough and the subsequent Taylor Report.
"English football is in a much better place than it was 27 years ago," writes Sir Alex. "Across the leagues, stadiums weren't what they should have been, the development of players was nowhere near as advanced as it is now, those controlling the game couldn't give the TV rights away, fans weren't treated properly and what interest there was in football from Government was negative.
"There are some with rose-tinted glasses who think football was great a generation ago, but nostalgia plays strange tricks with the mind. Back then, football’s role in the cultural make-up of the country was arguably in decline. It was a great shame."
Following extensive experience of guiding United around Europe, Sir Alex is confident the Premier League is comfortably the strongest domestic league in the world, citing the increased competition at the top of the table and the atmosphere at grounds around the country.
He continues: "Competition is healthy and it is what sets this league apart from others in Europe. The quality and entertainment of the football in the Premier League has increased year on year. It was always getting harder to go out and win the title, to find the right mix of players, youth, experience and attitude.
"The Premier League is known the world over for the passion and knowledge of its fans as well as the atmosphere in the grounds. Not just Old Trafford - the trips to Goodison, St James’, Anfield and White Hart Lane amongst others always produced fantastic support.
"It’s part of the history and tradition of the English game that drives its success today. I will miss all of it."
The full letter will be published with the Premier League official 2012-13 season review, due this week.